Vortex separator

ABSTRACT

A vortex separator is provided having an annular contaminant chamber for receiving centrifugally separated particles, and a baffle at the entry to or in the annular chamber, to inhibit the whirling of particles retained therein either in the absence of scavenge flow or because they are unable to escape from the chamber, to prevent abrasion of the walls by the spinning particles, while not interfering with the entry of the particles into the annular chamber, nor with normal scavenge flow, if any.

RELATED APPLICATIONS

This application is a division of application Ser. No. 360,516, filedMay 15, 1973, now U.S. Pat. No. 3,895,930 which, in turn is acontinuation-in-part of application Ser. No. 306,119, filed Nov. 13,1972, now abandoned, which, in turn is a continuation of applicationSer. No. 31,471, filed April 24, 1970 now abandoned.

Vortex separators comprise a tube through which particle-laden air ispassed, and a vaned deflector disposed within the tube in the path ofthe influent air stream to impart a helically spinning or cyclonicmovement to the air stream. The air-entrained dirt particles that arerelatively heavy are thrown to the periphery of the tube, due to thecentrifugal force of the vortex stream, thus cleaning the air ofparticles at the center of the tube. The clean air at the center isnormally drawn off from the center of the tube, and theperipherally-disposed dirt particles drawn off from or collected at theperiphery of the tube.

In such vortex separators, the clean air outlet is in the form of a tubeof lesser diameter corresponding to the central clean air zone, andcoaxial with and extending into the larger diameter vortex tube. Theperipheral vortex flow with the entrained particles enters an annularpassage open at each end and surrounding the clean air outlet tube, andthe particles are normally drawn off from the end of this by bleed orscavenge flow. It is, however, necessary to maintain flow through theannular passage, to prevent it being clogged by contaminants depositedthere, and ensure that the contaminants are carried off the by the flow.

Brandt Austrian Pat. No. 192,385 describes one way to overcome thisproblem. Brandt uses a vortex separator of conventional type, having atubular outlet member tapping the clean air flow in the center of thevortex, in which the helical flow of the gases in the vortex is utilizedto maintain the contaminants entrained in the gas in the annular passagesurrounding the outlet member. The end walls of the annular passage areprovided with a helix or spiral whose pitch conforms to the vortex ofthe contaminant-bearing gases, so as to maintain spiralling flow throughthe passage. To achieve this, the helix or spiral is placed midwaybetween the ends of the annular passage. The openings at each end of thepassage are unobstructed, so that the spiralling flow keeps the openingsfree of contaminant deposits at all times, as well as keeping theannular passage free of such deposits.

The efficiency of a vortex separator (i.e., the percentage of entrainedparticles that are separated) is a function of the centrifugal forcesdeveloped, the length of the spinning zone, and the proportion of thescavenge flow to clean air flow. Of course, an optimum clean air flow isalways the primary desideratum. Therefore, the flow of scavange airshould be controlled at the minimum to give effective particleseparation.

The measures required to control and limit scavenge flow create problemswhich heretofore have not been resolved when operation at asuperatmospheric pressure is desired. When a vortex separator isoperated at a high superatmospheric pressure, as for example whencleaning bleed air taken from the compressor of a gas turbine or jetengine, one way of limiting scavenge flow is to close off all or most ofthe outlet end of the annular passage to form an annular contaminantchamber and to exhaust the scavenge flow therefrom through a relativelysmall diameter opening, disposed in the side wall or at the closedbottom or end of the chamber. The flow rate of the scavenge air throughthis opening and the back pressure should be sufficient to give theneeded efficiency of the separator. Control over the scavenge air flowrate and pressure is maintained by selection of the diameter of thescavenge air opening, or by providing an orifice at the scavenge airopening or by providing an adjustable valve in the scavenge air opening.Where the supply of air is limited it may be desirable not to bleed aportion as scavenge flow. In such cases a scavenge air opening mayeither not be provided or be kept closed and the separated particlesretained within the annular contaminant chamber.

If a scavenge opening is not provided, is closed or becomes plugged, asby a particle too large to pass through, the particles that are throwncentrifugally into the peripheral cyclonic flow continue to enter theannular chamber, are retained there, and are subjected to a continuedcylonic or spinning flow. However, since they cannot escape from thechamber, they continue to whirl therein, and abrade the walls of thevortex tube within the annulus. This creates a serious problem. Evenwhile scavenge flow continues particles too large to pass through thescavenge air opening may whirl around the annular passage continuously,also resulting in abrasion. Eventually, the abrasion caused by thespinning particles will wear away the wall of the vortex tube, and causethe tube to fail.

Such a failure, depending upon the system in which the vortex separatoris utilized, can be catastrophic, and therefore must be prevented. Forexample, high pressure bleed air from the compressor is often employedin gas turbine or jet engines, to maintain the oil in the bearinghousing in contact with the bearings. The need for providing clean airis of course obvious, inasmuch as contaminant particles in contact withthe bearings can cause excessive weear and are quite dangerous. A vortexseparator inserted in the high pressure air line would be a usefuldevice to provide clean air. However, a failure in the vortex separatorin the line leading to the bearings can cause loss of pressurization,resulting in separation of the oil from the bearings, thus causing thebearings to overheat, and possibly cause a fire. If the engine is in useon an aircraft at the time of such a failure, it can cause loss of theaircraft. Therefore, a vortex separator cannot be put to such a useunless this abrasion problem is overcome.

Another difficulty presented when there is lack of scavenge flow is thatthe particles which build up within the annular chamber may be swept outthe open entrance, sometimes suddenly, and en masse, by the enteringcyclonic flow, and then enter the clean air stream. This, of course, canbe quite detrimental to downstream components in the system, and if theparticles do so en masse the effect can be worse than if the vortexseparator merely became inoperative.

In accordance with the present invention such difficulties are overcomeby providing a vortex separator having an annular contaminant chamberand a baffle at the entry to the chamber or in the chamber, effective inthe absence of scavenge exhaust flow to inhibit the whirling ofparticles retained in the annular chamber, while not interfering withthe entry of such particles into the chamber, or their exhaust therefromif possible, under normal conditions. The baffle may also, according toits design, inhibit the whirling of particles in the passage duringnormal scavenge flow, but this is an optional feature and not essential.As another feature, the baffle may also be designed as a closure toprevent the retained particles which build up within the chamber frombeing swept out in the clean air stream by the cyclonic flow in thevortex tube.

The vortex separator of the invention comprises a tubular body having aninlet at one end, and outlet at the opposite end, and a central passagetherebetween; a deflector coaxially mounted in the passage adjacent theinlet, and having a plurality of helical vanes abutting the wall of thepassage, and positioned at an angle to the line of flow from the inletto the outlet so as to create a vortex stream in the influent air, whichconcentrates the contaminant particles in the whirling air stream at theperiphery of the passage, thereby leaving the air at the center of thepassage relatively clean; a generally tubular member disposed within thecentral passage at the outlet end of the tubular body for delivery ofclean air from the central passage of the tubular body; said tubularoutlet member defining an annular contaminant chamber between theexterior of the outlet member and the interior wall of the centralpassage of the tubular body for receiving separated contaminantparticles; a wall extending between the tubular outlet member and thetubular body at the end of the annular chamber at the outlet end of thetubular body, closing off the annular chamber at that end; and a bafflehaving at least one opening and defining an inlet into the annularchamber and disposed in the line of cyclonic flow at or in the annularchamber and effective at least when scavenge flow ceases and,optionally, also while scavenge flow continues, to deflect the whirlingair stream in a manner to inhibit the whirling movement of the particlesretained in the chamber, and thus prevent abrasion of the wall of thetubular body there, substantially without interfering with the entry ofparticles into the chamber or with normal scavenge flow, the openinghaving a larger available open area than any outlet port from theannular chamber. Preferably, the annular chamber has at least one portfor scavenge flow from the chamber, controlling scavenge flow. Suchcontrol can be achieved by adjusting the size of the port, or by orificemeans or valve means in fluid flow connection with the port. The outletport has a lesser open area available for flow than the inlet or inletsto the annular chamber at the baffle.

Preferred embodiments of the vortex separator of this invention areillustrated in the drawings, in which:

FIG. 1 is a cross-sectional view of a vortex separator having a bafflein the form of a helical ring which is effective only in the absence ofscavenge flow;

FIG. 2 is an isometric view of the helical ring baffle utilized in thevortex separator of FIG. 1;

FIG. 3 is a cross-sectional view of another embodiment of baffle in theform of radial fins, which are effective both while scavenge flowcontinues and when it ceases;

FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 3,and looking in the direction of the arrows, showing the fins;

FIG. 5 is a cross-sectional view of another vortex separator havingfins, and also effective both with and without scavenge flow;

FIG. 6 is a cross-sectional view taken along the line 6--6 of FIG. 5,and looking in the direction of the arrows, showing the fins;

FIG. 7 is a cross-sectional view of another embodiment of vortexseparator utilizing the helical baffle of FIG. 2.

The baffle can be of any construction that obstructs whirling movementin the annular chamber when scavenge flow ceases, and optionally alsowhile scavenge flow continues, without substantially interfering withscavenge flow to and out of the annular chamber. The baffle musttherefore provide an entrance into the chamber for scavenge flow, ifany, and contaminant particles. Where provision is made for scavengeexhaust flow the entrance should be larger than the smallest flowopening in the scavenge flow outlet.

It is particularly important that the baffle not unduly obstruct orinterfere with scavenge flow, where an exhaust is provided, since theentrained particles that can be carried out from the vortex separatorshould remain entrained thereby. Any particles too large to pass throughthe outlet and therefore retained in the chamber should be quiescent, onthe other hand, so that they will not cause abrasion damage.

The baffle can take a form such that it separates the spinning velocityand longitudinal velocity components of air and/or particles enteringthe annular chamber so that spinning particles can pass freely. Thebaffle can also permit spinning flow to enter the annular passage, andalso block or inhibit whirling of the retained particles, or it canredirect spinning flow so that it becomes direct flow.

An example of the first-mentioned form of baffle is a flat ring closingoff the annular chamber at the entrance thereto or a short distancetherewithin. The ring has one or more apertures through which all flowthat enters the annular chamber must pass.

The size of the apertures in the ring should be large enough to permitall separated particles, whatever their size, to enter and should notdiminish scavenge flow in rate or volume, so that most of theair-entrained particles that can escape remain entrained, and escapethrough the outlet, of one is provided. A flat ring of this type iseffective when scavenge flow ceases, due to a blockage or otherwise, bypermitting the entry of particles through the aperture only in a directpath. The whirling air at the periphery of the vortex tube has littletendency to pass through the baffle into the chamber when there is noscavenge flow. Therefore, once within the chamber the centrifugal forcesof the cyclonic flow no longer act upon the particles, so that they mayharmlessly settle out within the chamber. In addition, during normalscavenge flow conditions spinning or whirling flow is usually inhibitedfrom entering, and only direct flow is possible. As a practical matter,the air in the annular chamber beyond the ring is relatively quiescent,and particles entrained in the direct flow will be exhausted. Anyparticles that are too large to pass through the exhaust outlet or tooheavy to remain entrained in the flow will remain within the annularchamber, but are quiet, and will not abrade the walls of the tubularbody.

The ring should completely close the entrance to the annular chamberexcept for the aperture or apertures which permit the entry of scavengeflow and entrained particles. In this manner, the ring serves as aclosure to retain the separated particles within the chamber in theabsence of scavenge flow. As the particles build up within the chamber,the ring prevents their being swept out by the cyclonic flow in thevortex tube.

In the simplest form, the ring is a flat washer, having a singleaperture through its solid portion. The outside diameter of the ring isapproximately equal to the inside diameter of the tubular body, and theinside diameter of the ring is approximately equal to the outsidediameter of the tubular outlet member, so that when installed it closesoff the greater part of the inlet to the annular chamber. The flat ringshould be disposed a short distance within the annular passage anddefines the inlet end of the annular chamber. This ensures that whirlingparticles which strike the ring will be held on the ring, will travelcircumferentially thereon until they can reach and enter an aperturethereof, and will not be deflected into and entrained in the clean airflow prior to their passage through the aperture into the annularchamber.

The ring can also be disposed at an angle to the axis of the vortexseparator. If the angle is approximately equivalent to or greater thanthe helix angle of the vaned deflector, one segment of the ring isparallel to the plane in which the whirling particles move, and if theaperture is located on this segment, at right angles to the plane offlow, the entrained particles will have to change direction by a 90°angle to pass through the aperture. Moreover, such an aperture preventsentry of the cyclonic flow, and inhibits whirling within the annularchamber both during and in the absence of scavenge flow.

If the angle is less than the helix angle of the deflector and theaperture is on a segment of the ring which is opposed to the directionof whirling particles are in effect scopped into the aperture, whilescavenge flow continues. When scavenge flow ceases or is not utilizedthe particles still enter readily due to their centrifugal momentum, butthe cyclonic flow does not, and the cyclonic flow forces acting upon theparticles within the chamber are thus greatly diminished by the presenceof the ring, since in the absence of scavenge flow the whirling air haslittle tendency to pass through the aperture to enter the chamber. Thering is thereby effective to inhibit the whirling of the particlestrapped within the chamber.

The aperture does not function as a restricting orifice. In order toprevent it from doing so, where scavenge flow is desired, the size ofthe aperture is sufficiently large and the thickness of the ringsufficiently small to permit the scavenge opening to control thescavenge flow, by whatever means at the opening is desired, such assize, an orifice, or a valve.

When the flow rate is high, it may be necessary to provide more than oneaperture in the ring. When a plurality of apertures are employed, eachmust conform to the proper size requirements to permit the passage ofthe entrained particles, without restricting flow rate.

The apertures can have any conventional shape, such as round, square orrectangular. They can be formed by drilling, punching, slitting orperforating, or cutting out a segment of the ring. Preferably, arcuateshaped openings extending radially across the annular passage from theinside wall of the tubular body to the outside wall of the tubularoutlet member are utilized to allow the particles easy access to theopening. An arcuate aperture can be formed simply by splitting the ringin one portion and adjusting the size of the gap by removing a radialsegment.

The baffle can also take the form of a split ring, formed into asingle-coil helix, resembling a lock washer, wherein the size of theaperture varies according to the pitch of the helix, and the gap betweenthe split ends of the ring. Such a helix can have a pitch eitherparallel or opposed to the direction of whirling. If the aperturebetween the ends of the helix is such that the whirling air stream mustchange direction, in order to pass through the aperture, the particleswill not enter readily, thus inhibiting their whirling motion in boththe presence and absence of scavenge flow. If the aperture in thehelical ring faces the oncoming flow in the whirling air stream, theparticles enter the aperture readily in the presence of scavenge flow,but when scavenge flow ceases, although the particles continue to enterreadily the baffle is effective to inhibit their whirling within thechamber. A helical baffle of this latter type is preferred where it isimportant to inhibit whirling only in the absence of scavenge flow, suchas in a vortex separator having no scavenge exhaust outlet in which theseparated particles are collected and retained within the annularchamber. While permitting the easy entry of the particles, the helixeffectively prevents the particles which build up in the chamber frombeing swept out.

If a helical baffle in which the aperture faces the whirling air streamis used in a vortex separator employing scavenge flow to exhaust theseparated particles, the pitch of the helix may be less than the pitchof the helical vaned deflector. In this manner the angular directionchange required for the flow and entrained particles to pass through canbe sufficient to inhibit whirling of large or heavy particles which aretrapped and retained within the chamber.

The ring, whether flat or helical, can be secured within the annularpassage by welding, brazing, bonding or by press fit. It may also beformed as an integral flange on the entrance end of the clean air outlettube. Other suitable means for attaching or forming the ring will beapparent to those skilled in the art.

The baffle can also be in the form of radial fins which extend partiallyor completely across the annular chamber parallel to the axial flowtherethrough, and either partially or completely from end to end of theannular chamber. When the whirling stream enters the annular chamber,whirling is halted by the obstructing fins, and direct axial flowresults. Since the fins extend radially across the annular chamber theydo not obstruct axial flow of entrained particles, nor are the entrainedparticles deflected into the clean air outlet. In addition, since thefins offer little resistance to scavenge flow, they have no adverseeffects on the efficency of the vortex separator.

When the fins extend partially across the annular chamber, they can befixedly attached to either the outside wall of the clean air outlet tubeor the inside wall of the separator body, or preferably both whereinthey are alternately attached to the body and the outlet tube, so that awhirling stream will have a tortuous path to follow, but a direct flowhas free passage. The fins should extend radially sufficiently acrossthe annular chamber to ensure that a complete circular path is notavailable to the whirling flow. Similarly, the fins should extendlongitudinally within the annular chamber a distance sufficient toensure that the whirling air must make contact therewith during onerevolution of the whirling air. The entrained particles also aredeflected by the fins. The heavier particles and those that are toolarge to pass through the outlet are separated out, and remain quiescentat the bottom portion of the annular chamber, while the smaller andlighter particles are vented via the scavenge flow opening.

When the fins extend completely across the annular chamber, they can befixedly attached to both the separator body and the clean air outlettube, so as to form a plurality of segmented annular chambers. Thewhirling flow that enters the annular chambers can only flow axiallytherethrough, since the fins prevent the circular movement of the flow.

The fins should not block the scavenge flow outlet or outlets. In thismanner, the fins do not prevent the passage of such entrained particlesas can escape to the outlet.

The number of fins required to inhibit or stop the whirling of thewhirling air stream is dependent upon factors, such as the angle of thefins, the diameter of the annular chamber, the flow rate, the pressure,and the spacing of the fins in the annular chamber. Three fins extendingradially completely across the annular chamber and disposedapproximately 120° apart are satisfactory to inhibit whirling withoutadversely effecting the particle separation efficiency. Such fins canextend longitudinally to the outlet end of the chamber with scavengeflow outlets provided at the outlet end of each chamber segment thusdefined by the fins.

Preferably, the baffle, whether it be in the form of an apertured ringor radial fins, is formed from the same or similar material as thevortex separator, to facilitate its welding, brazing, bonding orpress-fitting in place. By utilizing the same material as the separator,both will be subject to the same contraction and expansion, due totemperature changes. Since high pressure vortex separators are oftenused in high temperature systems, this is an important consideration.Usually, vortex separators for high pressure and temperature systems canbe constructed from metallic material, such as steel, stainless steel,aluminum, nickel alloys and the like. Where temperature and pressurerequirements are not extremely high, abrasion-resistant plasticmaterials, such as nylon, polytetrafluoroethylene, polypropylene,polycarbonate and polyphenylene oxide resins can be utilized.

The scavenge port is an opening in the side or end wall of the annularscavenge chamber. While more than one port can be provided, it isusually desirable to provide only one, since it can be larger andtherefore less likely to plug with contaminant. The opening ispreferably round, to reduce the likelihood of plugging, and ispreferably located in the side wall of the chamber, at a distance fromthe outlet end of the chamber greater than the diameter of the opening.This permits large or heavy particles which are trapped and retained inthe chamber to collect at the outlet end without blocking the scavengeport. If the unit is mounted with its axis horizontal, the scavenge portshould preferably not be on bottom, for the same reason.

The scavenge port is preferably formed as an orifice in the outside wallof the chamber, sized to provide the desired flow at the operatingpressures and temperatures. Connecting lines if provided shouldpreferably be larger than the orifice, to avoid any possibility ofplugging, and to avoid forming an inadvertent scavenge flow restrictionin the line. The port can be formed in the shape of a tube, which actsas both orifice and connecting line at the same time. Alternatively, acontrol valve may be connected to the scavenge port. Since the flowthrough this valve contains contaminant particles, the valve should bedesigned to be unaffected by the particles present. A gate valve,preferably used with a turbine type flowmeter, is suitable and a needlevalve can also be used, in low contaminant flows.

The design of the tubular body, the vaned deflector and the clean airtubular outlet member are important for the efficient operation of thevortex separator. It should be noted that the design of the baffle ofthe invention can be adapted to fit the design requirements of any ofthe other components. Therefore, the baffles can be efficiently utilizedin high pressure vortex separators of varying design, and willefficiently inhibit whirling in the annular contaminant chamber thereofso as to prevent the abrading of the body tube walls by whirlingparticles.

The vortex separator shown in FIG. 1 comprises a tubular body 1 with anopen central portion or vortex chamber 5, and formed of stainless steel,and having an inlet 2 for high pressure contaminated air, an outlet 3for clean air and a scavenge flow outlet line 4 for contaminated exhaustair. The scavenge flow outlet line 4 is in fluid flow connection withthe scavenge port 12, for exit of scavenge flow from the annular chamber8. A vaned helical deflector 6 is disposed within the center of thetubular body 1 to generate a vortex stream in the influent air whichconcentrates the contaminant particles in the whirling air stream at theperiphery of the passage 5, thereby leaving the air at the center of thepassage relatively clean. The outlet 3 has a tubular outlet member 7which has a peripheral flange 9 extending to the wall of the tubularbody 1 and terminating in a peripheral recess 9a, receiving the end ofthe tubular body. The outlet member 7 extends into the open centralportion 5 of the tubular body 1. The tubular member 7, flange 9 and theinside walls of the tubular body 1 define an annular chamber 8 for thepassage of scavenge flow and entrained particles. The flange 9 walls offthe outlet end of the annular chamber 8 so that the only exit is thescavenge port 12 leading to the scavenge flow outlet line 4. Thescavenge port 12 is disposed in the wall of body 1 with its centerlineat a distance from flange 9 equal to twice the diameter of the outlet.The port 12 is small, so that only contaminant particles below a certainsize can pass through, but the size of the port is made small not forthis reason but to restrict and control scavenge flow to an efficientlevel.

A baffle in the form of a helical ring 10 having aperture 11 which islarger than the scavenge port 12 is disposed within the entrance to theannular chamber 8. The ring extends from the outside wall of the tubularmember 7 to the inside wall of the tubular body 1, so that all air thatenters the annular chamber 8 must pass through the aperture 11. As shownin FIG. 2, the ring 10 is a single coil helix resembling a lock washer.The helical ring 10 is installed just within the entrance to the annularchamber 8, and has a pitch direction the same as the vortex stream, sothat the aperture 11 faces the whirling stream, and the entrainedparticles can freely pass therethrough with scavenge flow restricted tothe accomodated by scavenge port 12.

In operation, the vaned deflector 6 generates a vortex stream in thecontaminated influent air that enters via inlet 2. The vortex streamconcentrates the contaminant particles in the whirling air stream at thewalls of the tubular member 1, thus allowing them to enter annularchamber 8 via aperture 11 in the helical ring 10, and be discharged viathe scavenge flow port 12. The clean air in the center of the vortex istapped by outlet member 7 and is thus discharged via port 3. Wheneverthe scavenge flow ceases, due, say, to blockage of the port 12 byentrained particles, the helical baffle 10 is effective to inhibit thewhirling movement of the particles now retained within the chamber 8.The particles continue to freely pass through the aperture 11, due totheir centrifugal momentum, but once inside the chamber 8 the baffle 10of chamber 5 prevents the particles from being subjected to the cyclonicflow forces above the outlet member 7. The whirling motion of the air atthe periphery of the vortex tube does not continue past the baffle 10,due to the absence of scavenge flow while the port 12 from the chamber 8is closed. For this reason, the particles that enter the annular chamber8 will be quiescent, and failures caused by abrasion of particlesagainst the wall of the tubular body 1 are averted.

Even while scavenge flow continues, because of the restriction onscavenge flow imposed by the scavenge flow port 12, the whirling motionof the air is greatly restricted also, in chamber 8, beyond ring 10, andalthough entrained particles are carried out the port 12, the whirlingabrasive movement of retained particles is greatly reduced, if noteliminated altogether, so that such particles are sufficiently quiescentto overcome the abrasion problem. It is not necessary, to eliminate theabrasion that leads to failure of the wall, to prevent all movement ofparticles in the chamber 8, and indeed, while scavenge flow continues,some whirling flow is needed to keep particles that can escape entrainedin the flow, and carry them out the port 12.

In addition, the helical baffle 10 prevents the particles too large topass through the port 12, and that consequently are retained in theannular chamber 8, from escaping in the reverse direction, to return tothe vortex chamber 5. The baffle 10 prevents the whirling air stream inthe vortex chamber 5 from sweeping the collected particles out of theannular chamber 8. This permits the particles to be stored in thechamber until it is full, at which time it can be manually cleaned out.

It is thus evident that the vortex separator of FIG. 1 is effectivewithout a scavenge flow bleed of separated particles, i.e., wheneliminating or closing the scavenge port 12. The device then performs inthe same manner as when the scavenge flow outlet is blocked, asdescribed above. The separated particles are stored within the chamber 8and the helical baffle 10 inhibits their whirling to prevent abrasion ofthe chamber wall.

The baffle provided in the vortex separator shown in FIG. 3 are radialfins 15 and 16 which extend partially across the annular chamber 8, andare effective to inhibit whirling of separated particles in both thepresence and absence of scavenge flow. Fins 15 are fixedly attached tothe outlet tube 7 and are disposed approximately 120° apart. Fins 16 arefixedly attached to the separator body 1 approximately 120° apart, andare disposed alternately between the fins 15. Fins 15 and 16 both extendsufficiently across the annular chamber 8 in an overlapping manner sothat a complete circular path is not available to the air flow withinthe annular chamber. As shown in FIG. 4 the fins 15 and 16 extendlongitudinally within the annular chamber 8 to a point which isapproximately in line with the entrance to the scavenge flow port 12. Inthis manner the annular chamber remains unobstructed at the outlet, andthe fins do not prevent the exhaust of entrained particles. Inoperation, as the whirling stream enters the annular chamber it isdeflected by the fins, and proceeds in an axial flow path.

In the vortex separator of FIGS. 5 and 6 three radial fins 17 extendcompletely across the annular chamber 8, and all the way to outlet endwall 9' so as to form three segmented annular chambers 8a, closed at theoutlet and, each with a scavenge flow port 12' in fluid flow connectionwith an outlet line 4a in wall 9'. Since the fins prevent circularmovement of the flow, the whirling flow can only pass axially throughthe chambers 8a. Thus, the whirling stream is effectively dissipated,and damage to the separator body by whirling particles is prevented.

The vortex separator shown in FIG. 7 comprises a tubular body 21 with anopen central portion or vortex chamber 25, and formed of stainlesssteel, and having an inlet 22 for high pressure contaminated air, anoutlet 23 for clean air and a scavenge flow outlet port 32 in fluid flowconnection with the scavenge line 24 for contaminated exhaust air. Avaned helical deflector 26 is disposed within the center of the tubularbody 21 to generate a vortex stream in the influent air whichconcentrates the contaminant particles in the whirling air stream at theperiphery of the passage 25 thereby leaving the air at the center of thepassage relatively clean. The body 21 has an expanded portion 35 oflarger diameter at the outlet member 27 giving a large annular chamber28, for a purpose presently to be seen.

The outlet 23 has a tubular outlet member 27 which has a peripheralflange 29 extending to the wall of the tubular body 1 and terminating ina peripheral recess 29a in the end of the tubular body. The outletmember 27 extends into the open central portion 25 of the tubular body21. The tubular member 27, flange 29, and the inside walls of thetubular body 21 define an annular chamber 28 for the passage of scavengeflow and entrained particles. The flange 29 walls off the outlet end ofthe annular chamber 28, so that the only exit is the scavenge flow port32 which is in fluid flow connection with the outlet line 24 which isdisposed in the wall of the body 21. The scavenge flow port 32 and lineoutlet line 24 are small, so that only contaminant particles below acertain size can pass through, but the size of the port is made smallnot for this reason but to restrict and control scavenge flow to anefficient level.

A baffle in the form of a helical ring 30 having an aperture 31 which islarger than the port 32 is disposed within the entrance to the annularchamber 28. The ring extends from the outside wall of the tubular member27 to the inside wall of the tubular body 21, so that all air thatenters the annular chamber 28 must pass through the aperture 31. Asshown in FIG. 2, the ring 30 is a single coil helix resembling a lockwasher. The helical ring 30 is installed just within the entrance to theannular chamber 28, and has a pitch direction the same as the vortexstream, so that the aperture 31 faces the whirling stream, and theentrained particles can freely pass therethrough with scavenge flowrestricted to that accomodated by port 32.

In operation, the vaned deflector 26 generates a vortex stream in thecontaminated influent air that enters via inlet 22. The vortex streamconcentrates the contaminant particles in the whirling air stream at thewalls of the tubular member 21, thus allowing them to enter annularchamber 28 via aperture 31 in the helical ring 30, and be discharged viathe scavenge flow port 32. The clean air in the center of the vortex istapped by outlet member 27 and is thus discharged via port 23. Wheneverthe scavenge flow ceases, due, say, to blockage of port 32 by entrainedparticles, the helical baffle 30 is effective to inhibit the whirlingmovement of the particles now retained within the chamber 28. Theparticles continue to freely pass through the aperture 31, due to theircentrifugal momentum, but once inside the chamber 28, the baffle 30 ofchamber 25 prevents the particles from being subjected to the cyclonicflow forces above the outlet member 27. The whirling motion of the airat the periphery of the vortex tube does not continue past the baffle30, due to the absence of scavenge flow while the port 32 from thechamber 28 is closed. For this reason, the particles that enter theannular passage 28 will be quiescent, and failures caused by abrasion ofparticles against the wall of the tubular body 21 are averted. Evenwhile scavenge flow continues, because of the restriction on scavengeflow imposed by the scavenge flow port 32, the whirling motion of theair is greatly restricted also, in chamber 28, beyond ring 30, andalthough entrained particles are carried out the port 32, the whirlingabrasive movement of retained particles is greatly reduced, if noteliminated altogether, so that such particles are sufficiently quiescentto overcome the abrasion problem. It is not necessary, to eliminate theabrasion that leads to failure of the wall, to prevent all movement ofparticles in the chamber 28, and indeed, while scavenge flow continues,some whirling flow is needed to keep particles that can escape entrainedin the flow, and carry them out the port 32.

In addition, the helical baffle 30 prevents the particles too large topass through the port 32, and that consequently are retained, fromescaping in the annular chamber 28 in the reverse direction, to returnto the vortex chamber 25. The baffle 30 prevents the whirling air streamin the vortex chamber 25 from sweeping the collected particles out ofthe annular chamber 28. This permits the particles to be stored in thechamber until it is full, at which time it can be manually cleaned out.The widened portion 35 of the tubular body 21 enlarges the chamber 28providing a greater storage space for such particles.

It is thus evident that the vortex separator of FIG. 7 is effectivewithout a scavenge flow bleed of separated particles, i.e., wheneliminating or closing the scavenge port 32. The device then performs inthe same manner as when the scavenge flow outlet port is blocked, asdescribed above. The separated particles are stored within the chamber28, and the baffle 30 inhibits their whirling to prevent abrasion of thechamber wall.

Having regard to the foregoing disclosure, the following is claimed asinventive and patentable embodiments thereof:
 1. A vortex particleseparator with provision to prevent abrasion by separated particlesretained therein, and/or exhausted therefrom by scavenge flow,comprising a tubular body having an inlet at one end, an outlet at theopposite end and a central passage therebetween; a deflector coaxiallymounted in the passage adjacent the inlet, having a plurality of helicalvanes abutting the wall of the passage, and positioned at an angle tothe line of flow from the inlet to the outlet so as to create a vortexstream in the influent air, which concentrates the contaminant particlesin the whirling air stream at the periphery of the passage, therebyleaving the air at the center of the passage relatively clean; agenerally tubular outlet member disposed within the central passage atthe outlet end of the tubular body, for delivery of clean air from thecentral passage of the tubular body; said tubular outlet member definingan annular contaminant chamber between the exterior of the outlet memberand the interior wall of the central passage of the tubular bodyreceiving separated contaminant particles; a wall extending between thetubular outlet member and the tubular body at the end of the annularchamber at that end; and a plurality of fins in the annular chamberwhich extend radially from at least one wall of the annular chamber atleast partially across the annular chamber, to deflect the whirling airand particle flow and permit only axial flow, in a manner to inhibit thewhirling movement of the particles retained in the chamber, and thusprevent abrasion of the wall of the tubular body there, substantiallywithout interfering with the entry of particles into the chamber or withnormal scavenge flow.
 2. A vortex separator in accordance with claim 1in which the fins extend alternately from both the tubular outlet memberand the tubular body.
 3. A vortex separator in accordance with claim 1in which the radial fins extend completely across the annular chamber toform a plurality of segmented annular chambers.
 4. A vortex separator inaccordance with claim 1 in which the annular chamber has at least oneoutlet port for scavenge flow from the chamber controlling scavengeflow.
 5. A vortex separator in accordance with claim 4, in which thescavenge flow port is round.
 6. A vortex separator in accordance withclaim 4, in which the scavenge flow port further comprises outlet meansin fluid flow connection with the port.